WEIGHLOAD AUTOMATIC SAFE LOAD INDICATOR MK. I
MODELS 4, 5 & 6
The basic equipment consists of three main Items:-
(a) Control Box.
(c) Bell Unit.
Occasionally the following is supplied in addition:-
(d) Summator Unit, for use when a second Dynamometer is installed, e.g. on a separate Whip Hoist Rope.
(e) Remote Radius Indicator.
The Dynamometer is mounted in such a position that the hoist rope passes through it. According to the type of
crane, it may be rigidly mounted on the base section of the boom or on a 'swinging arm' frame which allows it to follow the
true path of the rope.
As the load on the hoist rope increases, the rope within the Dynamometer tends to straighten out, exerting an
increasing force on the center sheave which, in turn, applies an increasing force on the Hydrostatic Load Cell mounted
beneath it. The force on the Load Cell is converted to fluid pressure and transmitted through an armoured, flexible
capillary tube to the Control Box which is mounted at a convenient position within the vision of the crane operator.
The Control Box contains a dial with an adjustable range. The pressure from the Load Cell causes a black pointer
to rotate around this dial indicating, at all times,, the actual load being lifted or suspended.